Alvarado faced a lot of hitters yesterday though he'll probably get in too. If Soto didn't pitch now it would have been an equally big spot later probably.
They script this stuff, and then of course if you don't get the outs the script falls apart. But now Kerkering can finish it and they can still give the last two to Alvarado and Kimbrel. They had to know Soto wasn't going to get all three batters.